Glucose Control Study

Would you like to take part in the Glucose Control Study?

We are looking for people aged 40 – 65 years, who are overweight (BMI > 26 kg/m2) to take part in a research study.

What is the purpose of the study?

Certain milk fractions may have potential health benefits. Preliminary work has shown that a milk derived protein fraction improves glycaemic (blood sugar) control in healthy subjects – we now need to confirm this in people who are overweight and at risk of type 2 diabetes (T2D). Therefore this study aims to examine the effects of milk fractions, given in the form of a drink, on our ability to control circulating glucose (blood sugar) levels. These fractions are naturally occurring proteins found in milk.

Who can take part in this research?

Adults aged between 40 and 65 years, who are overweight or obese (BMI >26 kg/m2) but otherwise healthy may be suitable to take part. In order to participate in this study you should not:

  • have any chronic or infectious disease
  • be pregnant or breastfeeding
  • have any milk allergies or lactose intolerance

Your participation is entirely voluntary. Expressing an interest or committing to participate will not affect your right to withdraw at any time during the course of the study.

What will happen if I volunteer?

Initially, potential volunteers will be invited for a screening test at the Clinical Research Centre, St. Vincent’s University Hospital where we will explain the study in detail to you and ask you to sign the consent form. We will ask you to come for the screening test having fasted overnight (so no food after 8pm the night before, although water is allowed). We will measure your height, weight, waist circumference and blood pressure and take a blood sample (approximately 15ml/1 tablespoon of blood) to assess your glucose levels. We will also ask you to complete a short questionnaire. This visit should take approximately 1 hour.

What is involved in each of the study visits?

If you are eligible to participate and interested in taking part, you will be requested to attend the Clinical Research Centre at St. Vincent’s University Hospital on 3 separate mornings, having fasted overnight (so no food after 8pm the night before, although water is allowed). The 3 visits should take approximately 6-7 hours each and will take place 4 weeks apart. Before starting the study female volunteers will be requested to take a pregnancy test as pregnancy is an exclusion criterion.

Volunteers will be requested to consume a lipid based drink followed by either a milk shake containing the active milk fractions, intact milk (control milk) or a water control. Then over the next 4 hours we will monitor your glucose levels (and other related markers in the blood such as insulin and markers of inflammation) to see if glycaemic control (how the body handles sugars) is improved. Glycaemic control will be monitored using a euglycaemic clamp – which measures the balance between glucose and insulin (the hormone that clears glucose from the circulation) levels in the blood – to see if this is improved by the milk fraction.

The euglycaemic clamp involves taking a fasting blood sample, giving insulin and maintaining insulin at a certain level. The glucose is then given at different levels to maintain normal glucose levels. Blood sugar levels are measured every 10 minutes over a 4 hour period so that enough glucose can be given to keep blood sugar at normal levels.

We will give you one of the three test drinks on each of the three study occasions. A cannula (small thin tube) will be inserted into each of your arms and will remain there over the next 4 hours. We will take a number of blood samples from one cannula and we will use the other cannula to give you glucose (sugar) and insulin intravenously to measure how your body can regulate glucose concentrations. Using the cannula allows us to take a number of small blood samples throughout the test without having to pierce the skin multiple times. A total of 270ml of blood will be taken throughout the 4 hours. This is approximately ½ what is taken at a standard blood donation.

In this study, we will take a small muscle biopsy from your thigh. Muscle is a key organ for glucose control. This biopsy will allow us to assess the effect the milk fraction has in muscle. The muscle biopsy will take place during each morning visit to the Clinical Research Centre, St. Vincent’s University Hospital. This will involve numbing the area on your leg where we take the sample from, and then using a very fine needle we will take a small biopsy, about 45mg in total. This is approximately 1/10th of a paracetamol tablet. We would ask that you avoid strenuous activity for the 1 – 2 days after the biopsy. A doctor will be available to answer any questions you may have about the procedure. If you initially decide to take part you can subsequently change your mind without difficulty.

How will my data be used?

All of your data will be anonymised and kept strictly confidential at all times. Your biological data (blood glucose, insulin, etc. levels) will be used to determine whether there is any benefit in terms of glucose control in consuming a drink containing a novel milk fraction compared to a drink containing regular milk. The blood samples will be analysed for glucose, insulin and a number of other markers such as markers of inflammation present in the blood which give important indications of glycaemic function. The results may be published in the form of a scientific paper. Your data will be assigned a study code and this code will be used to put all the data from the study together in a secure password-protected database, where it will be stored safely for a minimum of 5 years. None of your details will be shared with any third parties. You will not receive any individual results for the study; please see the section on Risks and Benefits for clarity on this.

Your blood will be stored in a blood bank for a minimum of 5 years which is used for research purposes and may only be accessed after approval by the human research ethics committee. Identifying information about you will not be used in any reports of the research.

Are there any benefits from my participation?

You will not benefit directly from participation in this study. It is important to understand that this is not intended to replace any routine blood tests you or your doctor would have arranged. You will not receive individual results so this cannot be treated as part of your routine healthcare screening. Your test results will be communicated to your GP, who will contact you, should there be any abnormalities.

Are there any risks involved in participating?

This study is testing the effect of different milk proteins and as such there are no major risks involved. However some people may find it uncomfortable to give blood samples. As with all blood sample donation some individuals may feel dizzy or faint, if you have previously experienced these symptoms when having blood samples taken please inform the study researcher or medical personnel. There is a risk of bleeding, bruising and tissue necrosis associated with the cannula used for blood taking; however every effort will be taken to minimize this risk. There is also a risk of hypoglycaemia (blood sugar level becoming too low) associated with the IVGTT and the euglycaemic clamp however your blood sugar levels will be closely monitored throughout the test to minimize the risk of this occurring.

There is a slight risk of infection when carrying out a biopsy however sterile techniques are used during all sampling procedures to minimize this risk. The muscle biopsy will be obtained using a minimally-invasive microbiopsy technique under local anaesthetic. There may be a feeling of discomfort at this point. However, there may be some pain and delayed muscle soreness afterwards that feels similar to receiving a bruise to the leg, but this will ease after 48 hours. Complications are rare. However, biopsy can result in complications; such as bleeding or scarring at the biopsy site. The doctor is aware of such complications so that should one occur, prompt and appropriate treatment will be given. Temporary numbness of the skin near the biopsy site may also occur. This biopsy will be performed by a qualified medical doctor.

What will happen if you decide to take part?

If you decide you might want to take part, you can contact Elaine Kennedy, the researcher conducting the study using the contact details outlined below. The researcher will then arrange a suitable time and date to carry out the screening.

Compensation

The researchers involved in this study are adequately insured by University College Dublin.

Who is organising and funding this research?

This study is organised by University College Dublin and is funded by Enterprise Ireland through the Food for Health Ireland research programme.

You will not be paid for taking part in this research, however expenses related to the study such as parking costs will be covered.

Has this study been reviewed by an ethics committee?

The St. Vincent’s Healthcare Group, Ethics and Medical Research Committee have reviewed and approved this study.

Contact Details

Alternatively, please feel free to contact Elaine at nutritionresearch@ucd.ie or phone 086 7213854.